Remote control (RC) quadcopters are a type of remote control aircraft that uses four rotors to fly. Each rotor may be controlled by its own motor. A RC quadcopter is piloted by a user with a remote controller, also called a transmit controller. Radio signals from the controller control the motion of the quadcopter. A flight control processor in the quadcopter may combine radio signals from the controller with inputs from sensors on board the quadcopter to control the motion of the quadcopter. Sensors such as accelerometers, gyroscopes, and magnetometers may be used to estimate the quadcopter's position and attitude. However, magnetometers add to the cost and complexity of the quadcopter, and require calibration procedures to be performed by the user, or pilot. In addition, magnetometers are sensitive to magnetic interference, which can cause inaccurate readings and negatively affect the flight control process.
In addition to manually piloting the aircraft, some RC quadcopters permit a pilot to activate automated tricks. When a pilot activates an automated trick, the quadcopter may ignore commands from the pilot and perform a 360 degree flip, roll, or yaw rotation. When the automated trick is complete, the pilot may regain control of the quadcopter.
While automated tricks can be performed easily, the pilot is limited to selecting among the tricks offered by the quadcopter. If a pilot wishes to perform another maneuver, the automated tricks feature offers no assistance. It would be desirable if a quadcopter control system could offer the benefits of automated tricks while still permitting the pilot to remain in control of the quadcopter.